The present invention relates, in general, to control systems for powered doors and, more particularly, the instant invention relates to a control system for a passenger transit type vehicle door.
As is generally well known in the art, control systems for passenger transit vehicle doors must control the forces that are being applied to such doors during both the opening and closing strokes of the doors. At the beginning of a stroke of the door, acceleration forces are required and toward the end of the stroke deceleration forces are required.
It is known to employ a position encoder to supply door position information to the control system. Position information is used to obtain velocity information and the velocity of the door is controlled in an iterated feedback loop.
In prior art type door systems, the calculations needed for the iterated feedback loop place a massive burden on the central processor for the door. To limit this burden, the number of iterations per second is severely limited. This results in a relatively rough operation of the doors and thereby complicates the detection of obstructions.
In one aspect, the present invention provides a method of controlling a motorized door. The method includes generating, in a central processor for the door, one or more signals indicative of a predetermined door trajectory profile for a stroke of the door. The predetermined door speed profile provides an ideal velocity versus an elapsed time since a beginning of the stroke. The signals generated are communicated to a motion control processor. The motion control processor additionally receives door position signals from a position encoder. The motion control processor may be either: another committed microprocessor for the motor control, a high speed math processor such as a DIP, a Reduced Instruction Set Code processor (RISC), or a dedicated motor control processor chip which contains an algorithm enabling the device to regulate a motor via closed loop control processes. The motion control processor has within it an ideal trajectory profile from which it generates signals indicative of the required velocity of the door based on the door position signals and it generates error signals based on discrepancies between the velocity of the door and the ideal velocity. It generates motor control signals based on the error signals and the motor control signals are communicated to the motor of the door through a power amplifier.
In another aspect, the invention provides an apparatus for controlling a motorized door. It includes a central processor for generating one or more signals indicative of a predetermined door trajectory profile for a stroke of the door. The predetermined door trajectory profile provides an ideal velocity versus an elapsed time since a beginning of the stroke. The motion control processor is connected to the microprocessor to relay door position status back to such micro processor. The motion control processor is, also, connectable to a position encoder to receive signals indicative of the position of the door. Means are disposed in the motion control processor for generating signals indicative of a velocity of the door based on the signals indicative of door position, as well as means for generating error signals based on discrepancies between the velocity of the door and the ideal velocity. The motion control processor further includes a means for generating motor control signals based on the error signals. These motor control signals being for connection to a motor of the door.
It is, therefore, a primary object of the present invention to provide an obstruction detection system for a central processor controlled motorized door which does not place a significant workload on the central processor.
Another object of the present invention is to provide a control system for a motorized door which provides for smooth motion of the door.
An additional object of the present invention is to provide a control system for a motorized door which provides a feedback loop for motion control which has many iterations per second.
A further object of the present invention is to provide a control system for a motorized door which facilitates obstruction detection.
It is an additional object of the present invention to provide a control system for a motorized door which is consistent with an obstruction detection system that operates very quickly when an obstruction is detected.
It is another object of the present invention to provide a control system for a motorized door to control most types of vehicle and rail door systems being: plugged doors, pocket doors, outside sliding doors, folding doors and gull wing doors.
Still another object of the present invention is to provide a control system for a motorized door which is consistent with an obstruction detection system which is fail safe.
Another object of the present invention is to provide a control system for a motorized door wherein movement and obstruction detection are controlled by the same components.
Still another object of the present invention is to provide a control system for a motorized door that is capable of handling differing loads and masses of different door configurations.
An additional object of the present invention is to provide a method of reducing the workload of a central processor for a motorized door so that the central processor is free to perform other tasks.
In addition to the various objects and advantages of the present invention which have been generally described above, there will be various other objects and advantages of the invention that will become more readily apparent to those persons who are skilled in the relevant art from the following more detailed description of the invention, particularly, when the detailed description is taken in conjunction with the attached drawing figures and with the appended claims.